The most familiar polyhedron is a cube.

In a regular polyhedron, all of teh faces are congruent regular polygons and the same number of polygons meet at each vertex.

Polyhedron: a closed spatial figure composed of polygons called the faces of the polyhedron. (3-D figure made of polygons)
RAY_Polyhedron_Media.jpg
Polyhedron
Prism
: Polygons on top and bottom and rectangles on the outside.
Parellel Planes: two planes are parallel if and only if they don't intersect.
Half plane: is the portion of a plane that lies on one side of a line in the plane and that includes the line.
A Line Perpendicular to a Plane: Line is perpendicular to a plane P at point if it's perpendicular to every line in the plane that passes through P.
Dihedral Angle: Formed by two half planes with a common edge. Each half is called a face and the common edge of the half-planes is called the edge of the angle.

Diagonal of a right rectangular prism is..D squared = L squared + W squared + H squared

45-45-90 triangle: In any 45-45-90 triangle, the hypotenuse is square root of 2 times the length of a leg.

30-60-90 triangle: length of the hypotenuse is 2x time the length of the shorter leg, and the length of the longer leg is x times (square root of 3) times the length of the shorter leg

A line parallel to a plane:is a line that is not contained in a given plane is parallel to the plane if and only if it is parallel to a line contained in the plane

A regular polyhedron has congruent regular polygons as faces, with the same number of faces meeting at each vertex. There are only 5 convex polyhedron known and they are called Platonic solids.

Polyhedra are named for the number of faces that they have

quadrilateral- 4 sides
pentagon- 5 sides
hexagon- 6 sides
hectagon- 7 sides
octagon- 8 sides
nonagon- 9 sides
decagon- 10 sides